1. Field of the Invention
The present invention concerns a new process for preparing crystalline Form I of cabergoline.
2. Description of the Related Art
Cabergoline is an ergoline derivative interacting with D2 dopamine receptors and is endowed with different useful pharmaceutical activities and it is used in the treatment of hyperprolactinemia, central nervous system disorders (CNS) and other related diseases.
Cabergoline is the generic name of 1((6-allylergolin-8beta-yl)-carbonyl)-1-(3-dimethylaminopropyl)-3-ethylurea, decribed and claimed in U.S. Pat. No. 4,526,892. The synthesis of cabergoline molecule is reported also in Eur. J. Med. Chem., 24,421, (1989) and in GB 2,103,603. Crystalline cabergoline Form I, an anhydrous not solvated form of cabergoline, was prepared by crystallization from diethyl ether, as described in Il Farmaco, 50 (3), 175-178 (1995).
Cabergoline Form I, like cabergoline, displays a significant inhibitory effect with regard prolactine and has therapeutic properties that make it possible to treat patients who have pathological conditions associated with an abnormal prolactin level, thus is useful in human and/or veterinary medicine. Cabergoline is also active, alone or in combination, in the treatment of reversible obstructive airways diseases, for controlling intraocular pressure and for the treatment of glaucoma. It is also employed in the veterinary field, as antiprolactin agent and in cutting down drastically the proliferation of vertebrate animals. The several uses of cabergoline are for example described in WO 99/48484, WO 99/36095, U.S. Pat No. 5,705,510, WO 95/05176, EP 0 040 325.
Cabergoline Form I is particularly useful in the treatment of Parkinson's disease (PD), Restless Legs Syndrome (RLS), treatment of diseases like Progressive Supranuclear Palsy (PSP) and Multysystemic atrophy (MSA).